Finite-element analysis based on the full-vectorial H-field formulation has been established as one of the most powerful and accurate modal solution approaches for optical guided-wave devices. Among the available optical waveguides, those incorporating thin metal layers supporting the surface plasmon modes (SPMs) and coupling of these modes to dielectric modes have recently been proven to be attractive for many applications. In this paper, the H-field approach incorporating the perturbation technique is used in calculating the complex propagation characteristics of silver/polystyrene (PS)-coated hollow glass waveguides for terahertz frequency radiation. The propagation and attenuation characteristics of the SPMs at the metal/dielectric interfaces are presented. The formation of the coupled supermodes and the effect of the PS coating thickness on the attenuation characteristics of these waveguides are also investigated and shown to be critical to their design optimization.
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